The quantity of the vehicle is increasing rapidly in the recent years. This results in the additional air pollution due to exhaust gases. The vehicle emission accounts for 50-60% of air pollutant in some area crowded with vehicles, especially in the cities and metropolitans. Nowadays, people take great importance to the survival environment, and air pollution treatment has become a sensible topic. In order to decrease the vehicle emission, three measures will be adopted: Treatment before the motor, in the motor and after the motor (after-treatment). With the increasing stringent emission standard, the after-treatment becomes more and more important. The after-treatment device for vehicle (especially for the diesel vehicle) is made of three parts: the envelope, the particulates filter and the catalyst. The characteristics of the catalyst and filter determine the quality of the after-treatment device and play a vital role to the after-treatment.
Studying carefully the prior art nowadays, such as which disclosed by a Japanese company NGK, French company IBIDEN, they have used the pure SiC material to produce the particulates filter (see EP 1142619A1). The extrusion process has been applied to produce the product. Because of the specificity of the production of SiC particulates filtration substrate, the adhesion was used to combine the substrate together forming a particulates filter. The world well known way is used to plug the cell alternately to get the wall flow structure. The particulates filter can be used in the filtration and the regeneration of particulates matters. The refractory temperature of the pure SiC material is very high which can be up to 2200° C., so it has great advantage in standing for the high temperature during the course of filtration and regeneration of particulates matters.
Nevertheless, the temperature of sintering is very high which has described in the EP1142619A1 Article [0065] that “The sintering temperature is set to 2100° C. to 2300° C. in the present embodiment to obtain the average pore diameter of 6 μm-15 μm and a porosity of 35% to 50%. Further, the sintering time is set to 0.1 hours to 5 hours. Further, the interior of a furnace has an inert atmosphere during sintering, and the pressure in that atmosphere is the normal pressure”. Because the sintering temperature is much higher than 2000° C., this kind of production needs the high quality sintering equipments and instruments as well as huge investment. Furthermore, the sintering procedure is under an inert atmosphere. The production art is very sophisticated and consumes great amount of energy. The consequence is the high cost of product. This is the main drawback for the application especial for the developing countries. Higher quality/price ratio of the product is the key problem to be solved in the technical field in order that the product can be applied in the automobile industry world wide.